GlaxoSmithKline PLC - Replacement Director/PDMR Shareholding

The announcement that was released with reference number 7699X at 18:23 on 20 February 2012 contained an error relating to the adjusted free cash flow target, a performance condition for the vesting of GlaxoSmithKline (Other OTC: GLAXF.PK - news) 2009 Performance Share Plan awards granted to the individuals set out below in 2009. The correct adjusted free cash flow achieved was £16.5bn and not £17.4bn as previously stated. This announcement replaces the previous version.

Save (Milan: SAVE.MI - news) as disclosed above, all details concerning the vesting of the awards remain unchanged. The full amended text is shown below.

Notification of Transactions of

Directors and Persons Discharging Managerial Responsibility

Vesting of conditional share awards under GlaxoSmithKline Performance Share Plan

This notification sets out information relating to the vesting of conditional share awards granted in 2009 under the GlaxoSmithKline 2009 Performance Share Plan (the Performance Share Plan). The awards made to the individuals listed below vest after three and four year performance periods which are dependent on stretching performance targets of relative total shareholder return (TSR (Munich: 869159 - news) ) and a three year adjusted free cash flow target. As set out below, less than 50% of these awards vested at the end of the three year performance period.

The vesting of the awards under the Performance Share Plan was subject to the following performance conditions:

i) 40% of the award was subject to an adjusted free cash flow target measured over three years (1 January 2009 to 31 December 2011). The Company achieved adjusted free cash flow of £16.5bn, against a target of £16bn, over the three year period and therefore the Remuneration Committee has confirmed that 100% of this element of the award vested. This accounts for 40% of the total overall award.

ii) The balance of 60% of the award was based on TSR, measured over three and four years as follows:

a) half of this element (i.e. 30% of the total award) was measured over three years (1 January 2009 to 31 December 2011); and,

b) the remaining half of this element (i.e. the remaining 30% of the total award) will be measured over four years (1 January 2009 to 31 December 2012).

For the three year period 1 January 2009 to 31 December 2011, the Company's TSR ranked 6^th (i.e. in median position) against a comparator group of 11 pharmaceutical companies and therefore the Remuneration Committee has confirmed that 30% of the three year portion of the TSR element vested (i,e, 9% of the total award) and the balance of the three year portion lapsed. The four year portion of the TSR element (i.e. the remaining 30%) will be measured in February 2013 after the end of the four year performance period on 31 December 2012.

Therefore 49% of the total award vested and the balance of the awards subject to the three year performance period lapsed.

The table below shows the proportion of these Performance Share Plan awards that vested and lapsed on 17 February 2012, including dividends reinvested since the date of grant, and the proportion of the awards subject to the four-year TSR performance period which remain outstanding for the following individuals:

* denotes an Executive Director

The Company, Executive Directors and PDMRs were advised of these transactions on 20 February 2012.

The closing middle market price of an Ordinary share of GlaxoSmithKline plc on 17 February 2012 was £14.14.

This notification is made in accordance with Disclosure and Transparency Rule 3.1.4R(1)(a).

V A Whyte

Company Secretary

20 February 2012